If hydraulic clutch, try bleeding. If cable clutch, adjust the cable, if possible. Doubtful that you actually need a clutch, since having trouble getting into gear is a symptom of the clutch not fully disengaging. Which COULD be a pressure plate issue, but a dying clutch is much more likely to just start slipping.
Could also be a shifter issue. If there is a 'pivot ball' kind of deal at its base, that could be getting worn and sloppy. Or there is some other linkage issue.
Looks like that shifter uses a linkage with solid bars (no cables). I would be willing to bet a rubber bushing ejected itself. They will start to get mushy and ripped but often not present very noticeable symptoms. Then one day, they just decide they've had enough and the whole bushing, or at least a decent bit of it, decides it doesn't want to be a part of your car anymore.